Problem: A permutation p is an ordered group of numbers p1, p2, ..., pn, consisting of n distinct positive integers, each is no more than n. We'll define number n as the length of permutation p1, p2, ..., pn.

Simon has a positive integer n and a non-negative integer k, such that 2k ≤ n. Help him find permutation a of length 2n, such that it meets this equation: <image>.

Input

The first line contains two integers n and k (1 ≤ n ≤ 50000, 0 ≤ 2k ≤ n).

Output

Print 2n integers a1, a2, ..., a2n — the required permutation a. It is guaranteed that the solution exists. If there are multiple solutions, you can print any of them.

Examples

Input

1 0


Output

1 2

Input

2 1


Output

3 2 1 4


Input

4 0


Output

2 7 4 6 1 3 5 8

Note

Record |x| represents the absolute value of number x. 

In the first sample |1 - 2| - |1 - 2| = 0.

In the second sample |3 - 2| + |1 - 4| - |3 - 2 + 1 - 4| = 1 + 3 - 2 = 2.

In the third sample |2 - 7| + |4 - 6| + |1 - 3| + |5 - 8| - |2 - 7 + 4 - 6 + 1 - 3 + 5 - 8| = 12 - 12 = 0.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

public class Main { 
    public static void main(String[] args) { 
        InputStream input = System.in;
        OutputStream output = System.out;
        InputReader2 in = new InputReader2(input);
        PrintWriter out = new PrintWriter(output);
        Solution s = new Solution();
        s.solve(1, in, out);
        out.close();
    }

    static class Solution { 
        
        double EPS = 0.0000001;
        public void solve(int cs, InputReader2 in, PrintWriter out) {
            int n = in.nextInt(), k = in.nextInt();
            for (int i = 0; i < n; ++i) {
                if (k > 0) {
                    out.print((2*i+2) + " " + (2*i+1) + " ");
                } else {
                    out.print((2*i+1) + " " + (2*i+2) + " ");
                }
                k--;
            }
            out.println();
            

        }

    }

    static class InputReader { 
        BufferedReader br;
        StringTokenizer st;
        
        public InputReader(InputStream i) {
            br = new BufferedReader(new InputStreamReader(i), 32768);
            st = null;
        }

        public InputReader(FileReader s) {
            br = new BufferedReader(s);
            st = null;
        }

        public String next() {
            while (st == null || !st.hasMoreTokens()) {
                try { 
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return st.nextToken();
        }

        public int nextInt() { 
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() { 
            try { 
                return br.readLine();
            } catch (IOException e) { 
                throw new RuntimeException(e);
            }
        }
    }
    static class InputReader2 {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;

        public InputReader2(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new RuntimeException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0; // long or int
            do {
                if (c < '0' || c > '9') {
                    throw new RuntimeException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public double nextDouble() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0, div = 1;
            do {
               res *= 10;
               res += c - '0';
               c = read();
            } while (c >= '0' && c <= '9');
            if (c == '.') {
                while ((c = read()) >= '0' && c <= '9') {
                    res += (c - '0') / (div *= 10);
                }
            }
            return res * sgn;
        }
        public String next() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        } 
        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
    }
    static class Edge implements Comparable<Edge> {
        int to, dis;
        public Edge(int to, int dis) {
            this.to = to;
            this.dis = dis;
        }
        @Override
        public int compareTo(Edge other) {
            return Integer.compare(this.dis, other.dis);
        }
    }

    static class Reader {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;
        public Reader(){
            din=new DataInputStream(System.in);
            buffer=new byte[BUFFER_SIZE];
            bufferPointer=bytesRead=0;
        }

        public Reader(String file_name) throws IOException{
            din=new DataInputStream(new FileInputStream(file_name));
            buffer=new byte[BUFFER_SIZE];
            bufferPointer=bytesRead=0;
        }

        public String readLine() throws IOException{
            byte[] buf=new byte[64]; // line length
            int cnt=0,c;
            while((c=read())!=-1){
                if(c=='\n')break;
                buf[cnt++]=(byte)c;
            }
            return new String(buf,0,cnt);
        }

        public int nextInt() throws IOException{
            int ret=0;byte c=read();
            while(c<=' ')c=read();
            boolean neg=(c=='-');
            if(neg)c=read();
            do{ret=ret*10+c-'0';}while((c=read())>='0'&&c<='9');
            if(neg)return -ret;
            return ret;
        }

        public long nextLong() throws IOException{
            long ret=0;byte c=read();
            while(c<=' ')c=read();
            boolean neg=(c=='-');
            if(neg)c=read();
            do{ret=ret*10+c-'0';}while((c=read())>='0'&&c<='9');
            if(neg)return -ret;
            return ret;
        }

        public double nextDouble() throws IOException{
            double ret=0,div=1;byte c=read();
            while(c<=' ')c=read();
            boolean neg=(c=='-');
            if(neg)c = read();
            do {ret=ret*10+c-'0';}while((c=read())>='0'&&c<='9');
            if(c=='.')while((c=read())>='0'&&c<='9')
                ret+=(c-'0')/(div*=10);
            if(neg)return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException{
            bytesRead=din.read(buffer,bufferPointer=0,BUFFER_SIZE);
            if(bytesRead==-1)buffer[0]=-1;
        }

        private byte read() throws IOException{
            if(bufferPointer==bytesRead)fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException{
            if(din==null) return;
            din.close();
        }
    }
}